package com.xzy.sms.utils;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * @desc 
 * @author wjw
 * @time 2017年11月16日下午2:37:44
 */
public class MD5 {
    
    /***
     * 全局数组
     */
    private final static String[] strDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
    
    /** 构造 **/
    public MD5() {
    }
    
    /***
     * 返回形式为数字跟字符串
     * 
     * @param bByte byte
     * @return string
     */
    private static String byteToArrayString(byte bByte) {
        int iRet = bByte;
        if (iRet < 0) {
            iRet += 256;
        }
        int iD1 = iRet / 16;
        int iD2 = iRet % 16;
        return strDigits[iD1] + strDigits[iD2];
    }
    
    /****
     * 返回形式只为数字
     * 
     * @param bByte byte
     * @return String
     */
    private static String byteToNum(byte bByte) {
        int iRet = bByte;
        if (iRet < 0) {
            iRet += 256;
        }
        return String.valueOf(iRet);
    }
    
    /****
     * 转换字节数组为16进制字串
     * 
     * @param bByte byte
     * @return String
     */
    private static String byteToString(byte[] bByte) {
        StringBuffer sBuffer = new StringBuffer();
        for (int i = 0; i < bByte.length; i++) {
            sBuffer.append(byteToArrayString(bByte[i]));
        }
        return sBuffer.toString();
    }
    
    /****
     * 得到md5
     * 
     * @param strObj String
     * @return String
     */
    public static String GetMD5Code(String strObj) {
        String resultString = null;
        try {
            resultString = new String(strObj);
            MessageDigest md = MessageDigest.getInstance("MD5");
            // md.digest() 该函数返回值为存放哈希值结果的byte数组
            resultString = byteToString(md.digest(strObj.getBytes()));
        } catch (NoSuchAlgorithmException ex) {
            ex.printStackTrace();
        }
        return resultString;
    }
    
}
